Process for the manufacture of casein



June l1, 1929A. w. H. SHEFFIELD 1.716.799,

PROCESS FOR THE MANUFACTURE CASEIN Filed Aug. 2l, V1925 WAT Patented June UNITED 'sTATEs' PATENT OFFICE.

WILLIAII E. SHEFFIELIL OF HOQBABT, YORK.v

rincones non THE MANUFACTUBE or casEiN.

Application lcdlAugust A2 1, l1925. Serial lo. 51,708.

My invention relates to a process for the preparation of acid has for its special o a casein of this type which is substantially as good, that is to say, is available for many manufacturing purposes, as self-soured (natural) casein particularly for use in coating at certain other paper which has blanc fixe fillers incorporated therewith. I have found that by reducing the vnormally high ash content of acid casein to the' proportion of ash content'in self-soured casein, or lower, I am enabled to use acid casein for many purposes for which heretofore only self-soured casein could be used.

In carrying out my acid to the skim milk, preferably in a continuous manner, the milk being heated 'to such a temperature, and the proportion of -acid (preferably muriatic) being such that the resulting curd tends to form relativel small granules, know to the art as grain cur but not so vsmall as to incur the danger of glomerating into large particles.

the casein from the whey,

that the milk hasl been preheated, as hereinabove stated), but I do subject the separated casein to a very lthorough washing or proportion ofvso to several washings, preferably in a continu- Ious manner. I am aware of the fact that acid preciptated curd has heretofore been ,thoroughly washed with water but such washing removed only a comparativel)7 small the ash content,"unless possibly the washing was 'continued lto a comnercially impracticable extent. Howevei, by my method most, if not all, of said ash'con- -tent` of the reaction .products as is held in v y solutionv or in suspension in the whey is re moved before it has an opportunity to be ocg eluded in the casein and t e casein is broken up into particles of comparatively small size, or, kept from agglomerating into large recipitated casein andV ject the production of invention I add the skilled in the art. I mix the milk and l or kept from agr Vtion -of the screw conveyer,

particles, and therefore more readily accessibleto the subsequent washing treatment.

4I nthe drawing accompanying this application, which illustrates o ne form of an .apparatiis suitable for carrying out my process, Fig. 1 is a side elevation partly in section of one form of a complete apparatus, drawn to scale, embodying my invention and for carrying out the process hereinabove described; Fig. 2 is an enlarged cross-sectional detail on the .line 2--2 of Fig. 1; Fig. 3 is a eoI detail view, side and-crosssectional,-of a f portion of a ribbon flight forming part of the mixing conveyer shown in Fig. 1; Fig. 4 is a detail view, side and cross-sectional, of a portion of the solid flight forming part of the mixing conveyer shown in Fig. 1; Fig.

5 is an enlarged elevation' of the acid tank,`

iioat tank and mixing box shown in Fig. 1, and Fig. 6 is an enlarged detail plan View of the mixing box shown in Fi 1.

- A is a milk storage tank an B an acid storage tank. C is a milkheater of a well known type now on the market, in which the heat is conveyed to the milk -by hollow copper disks indicated by c. As any suitable milk heater may be used no further details of the milk heater are shown in the drawing. The milk heater is fed from the milk storage tank through pipe kc2 which may, and

referably is, provided with a flow control indicated, but not illustrated, by 0 3. D is a float flow controller for keeping constant the ilow of acid from tank B to intermediate baiiled mixing box F where it is mixed with the milk flowing from C through a vpipe g.

.90 tank E from which the acid flows into a f From the mixing box F the mixed milk' and acid pass in 4 a continuous manner into a screw conveyer H of any suitable construction, I prefer, however, to have alternate sections of this lconveyer,

for instance, in l the apparatus illustrated, the first and third i quarter, of the conveyer flight, in the form of a helicoid ribbon as indicated in Fig.' 3, the remaining sections being solid as shown in Fig.'v 4. The helicoid ri bon apparently produces a better mixing than the solid porportion acts not only as a positive forward feeder but also as a retarder to prevent too fast a forward movement ofthe curd and whey. In order that the screw conveyer H may be selfsdraining, it is slivhtly slanted downwardly in the direction o? feed, but, to

"prevent the liquid matter from leaving the while the solidconveyer ahead of the solid matter, each conveyer is provided with a suitable preferably interchangeable, gate, such as h Fig. 4.

Through a suitable spout I the contents of the screw conveyor H discharge in a continuous manner into a cylindrical screen or strainer K rotatabl mounted on suitable bearings and preferably tilted downwardly in the direction of feed. The whe passes through the screen into a receptaclilJ l.. rom which it Hows through pipe Z to thel usual sugar recovery tanklnot shown). IThe curds droa into a second screw conveyor N provided with a suitable flight, for instance, like the one in conveyor H, where they are mixed with water flowing through pipe O, and are fed through a spout P into screen Q, and from there into a third screw conveyor lit, similar to conveyors H and N, the wash water dropping into a receptacle S and passing thereiirom through pipe sinto one of the settling tanks hi, M. After passing through conveyer R where they are further washed by water entering through pipe e, the curds pass through .spout T, and 'strainer U into a suitable receptacle (not shown), the wash water passing into receptacle V and thence 'throng l pipe ff into one oi the settling tanks Sposta P, T, screens Q il, and receptacles Si, if, are like, and perform the same functions spout l, screen and re- ,cle L, rc pectively, and confie-yer rms the same function as coni/"eyA r li. All the parte oi the apparatus are, of Vcourse s 9 ci eleainess no showing has been made of some oi such supports.

The drawing shows the apparatus with all the conveyers and screens shown in proportion, and drawn tol scale, the total length of the mixing conveyor H proper not including the spout l being approximately 491/2 vfeet. i am, i course, not restrictedto the use ci an apparatus of these proportions or even of this kind but so far as l' am at present devised El believe that it iliustrates the most ecient form. The length o the screw conveyers H, N and R, respectively, should be sucient to permit a thorough :mixing of, and reaction between, the milk and acid, and a thorough washingfoi the curds, respectively. A

As already stated, in order to obtain a casein havin as low an ash content as practically possib e, it is highly advisable to preheat the milk t/c such a temperature and to use such a proportion ci acid that theresulting curd tends to form relatively small ranules known to. the art as grain curd. are should be taken not to precipitate the casein, or any substantialproportion there of, in such fine particles that they are able.

to pass through the screens, as this would mean either a total loss of such particles or the necessity of recovering such casein from uit-ably supported but for the sake the whey or wash water. 'lhose skilled in the art ci manufacturing casein are 'familiarA volume oi milk passing through the mixing box F that a sample of whey taken from the conveyer H about midwa between its ends tests l/ of 1% on a lactic acid basis. As, however, milk shows great variations in reard toquality, particularly acidity, l make irequent tests for whey acidity, preferably about every twenty minutes, and increase or diminish`the dow of acid into the mixing box according to results shown. It may possibly bel advisable at times to heat the milk to a somewhat higher or somewhat lower temperature than that indicated, but this is a matter which the casein chemist iully understands.

ln an apparatus having conveyers of the proportion oi' those shown in the drawing, l so regulate the speed of the flight in conveyor H that the acid and milk, or curd and whey resy ectivel"v `sass from one end oi such con- J a .t 4

action of the water upon the ash in the material passing through conveyors N and R, although in that case i prefer to acidulate only the water passing into'conveyer N so that the acid may again be washed out in conveyer R.

The milk and acid are mixed during ltheir passage between the bales in the mixing box F, but the complete separation of whIe-y and casein `begins only in the conveyer in an apparatus proportioned and operated as shown and described, the reaction hetween acid and milk is substantiall complete when the material has travelle about one-half the length of the conveyer. It will -be noted that the reaction takes place while the material is being constantly agitated in icc -12:5 the conveyer H and lthat after the reac only a very thorough mixing of acidA and milk during the reaction but also a subdivision of the curd into small granules, thus maintaining a lcondition in which very little soluble ash isoccluded and in which the major portion of the insoluble ash is made accessible to the solvent action of the acid whey.l The whey being promptly removed and the curd, therefore, not being permitted to settle Vin the whey, the danger of occluding ash by settling is obviated. `The grain curd being in the form o relatively small granules 1s more readily accessible to the solventandA other cleansing action of the wash water in conveyers N and R. I thus obtain a large reduction of ash content. Thus, tests made with an apparatus operated as hereinabove described and comprising conveyers of the number and proportion disclosed, resulted in an average ash content of the casein (dry) as it passed out of conveyer H, of 3.59%. Under the same conditions the proportion of ash content of the casein passing out of conveyer N was 2.68%, and out of conveyor R 2.21%. The resulting casein is thin flowing and does not jell. By the removal of so large a proportion of the ash, the size or glue produced by customary solvents is increased in strengt from 25% to 30%. By m process the proportion of butter fat, mil( sugar and acid residues are also reduced to a minimum. I claim: l.

1. The improvement in the process of manufacturingacid recipitated casein which consists in adding acid to milk, agitating the mixture until the reaction is completed and then separating the whey from the curd immediately after the agitation ceases, thus preventing the curd 'from settlin in the whey.

2. T e improvement in the process of manufacturing acid precipitated casein which consists ,in adding acid to milk under conditions which will cause the curd to form as grainy curd, agitatingthe mixture until .the reaction is completed and then separat ing the whe from the curd immediately after the ag1tation ceases, thus preventing the curd from settling in the whey.

v3. The Vimprovement in the process of manufacturing' acid precipitated casein which consists in adding acld to milk, agitatin the mixture until the reaction is complete separating the whey from the curd immediately after the agitation ceases, thus preventin the curd from settling in the whey, ad ing water to the curd, agitating the curd in the water and then separating 5. The improvement' in the process of.

manufacturing acid preci itated casein which consists in adding aci to milk under conditions which will cause the curd to form as grain curd, agitating the mixture while conducting ity over a confined path of predetermined length suiicientto permit the reactionto be completed, and then separating l the whey from` the curd immediately after the agitation ceases so as to prevent the curd from settling in the whey.

6. The improvement 1n the process of manufacturing acid precipitatedy casein which consists in adding acid to milk under conditions which will cause the curd to form as grain curd, agitating the mixture while conducting it over a'conned path of ipredetermined length sutlicient to permit the reaction to be completed, separating the whey from thecurd immediatelyl after the agitation ceases so as to prevent thecurd y'from settling in the whey, adding water to the curd, agitating the curd in the water while conducting both over a confined path of predetermined len th suiicient to permit the curd to be washe to the desired extent andthen separating the water from the curd.

WILLIAM H. SHEFFIELD. 

